
package org.apache.solr.schema;

import java.io.IOException;
import java.util.Map;
import org.apache.lucene.index.IndexableField;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.queries.function.valuesource.FloatFieldSource;
import org.apache.lucene.search.SortField;
import org.apache.solr.response.TextResponseWriter;
import org.apache.solr.search.QParser;
/**
 * A legacy numeric field type that encodes "Float" values as simple Strings.
 * This class should not be used except by people with existing indexes that
 * contain numeric values indexed as Strings.  
 * New schemas should use {@link TrieFloatField}.
 *
 * <p>
 * Field values will sort numerically, but Range Queries (and other features 
 * that rely on numeric ranges) will not work as expected: values will be 
 * evaluated in unicode String order, not numeric order.
 * </p>
 * 
 * @see TrieFloatField
 */
public class FloatField extends PrimitiveFieldType {

    @Override
    protected void init(IndexSchema schema, Map<String, String> args) {
        super.init(schema, args);
        restrictProps(SORT_MISSING_FIRST | SORT_MISSING_LAST);
    }

    @Override
    public SortField getSortField(SchemaField field, boolean reverse) {
        field.checkSortability();
        return new SortField(field.name, SortField.Type.FLOAT, reverse);
    }

    @Override
    public ValueSource getValueSource(SchemaField field, QParser qparser) {
        field.checkFieldCacheSource(qparser);
        return new FloatFieldSource(field.name);
    }

    @Override
    public void write(TextResponseWriter writer, String name, IndexableField f) throws IOException {
        String s = f.stringValue();

        // these values may be from a legacy lucene index, which may
        // not be properly formatted in some output formats, or may
        // incorrectly have a zero length.

        if (s.length() == 0) {
            // zero length value means someone mistakenly indexed the value
            // instead of simply leaving it out.  Write a null value instead of a numeric.
            writer.writeNull(name);
            return;
        }

        try {
            float fval = Float.parseFloat(s);
            writer.writeFloat(name, fval);
        }
        catch (NumberFormatException e) {
            // can't parse - write out the contents as a string so nothing is lost and
            // clients don't get a parse error.
            writer.writeStr(name, s, true);
        }
    }

    @Override
    public Float toObject(IndexableField f) {
        return Float.valueOf(toExternal(f));
    }
}
